74 



pluvial period, wlicn rains heavier than even those which now fall 

 iu the Bay of Bengal poured torrents over the land arranging and 

 re-arranging the gravel beds, which as the streams cut their way to 

 lower levels, formed protecting caps to the underlying and softer 

 beds, and in this manner may be accounted for the presence of the 

 beds of gravel at elevations of four hundred feet, as in the wood 

 above the Selling tunnel; three hundred near The Gate public- 

 house, on the Bjughton road; two hundred and twenty seven feet 

 at Rough Common ; two hundred and twenty at the Wliitstable 

 railway tunnel ; two hundred in the Park above Hales Place ; one 

 hundred and fifty at Broad Oak ; one hundred and thirty five at 

 Westbere ; and ninety feet at the Halfway House on the Kamsgate 

 road. 



On the south cast side of the valley there are also elevated 

 gravel beds as at the Old Park, one hundred and fifty feet ; Scot- 

 land Hills, one hundred feet. A.lso irregular patches of gravel, as 

 in Bigberry wood near the Chartham Hatch schools, two hundred 

 and fifty five feet ; in the same wood above Tunford, two hundred 

 and forty nine feet ; Theread wood, half a mile east of Hernhill, 

 three hundred feet ; Clapham hill, Whitstable road, two hundred 

 and twenty feet; Thornden wood, three liundicd feet; and Broom- 

 field, one hundred and seventeen feet. But as the rivers of the 

 district cut their way to lower channels, beds of the same gravel 

 were left in patches and terraces at much lower but varying lieights, 

 in some instances at two hundred feet below the higher beds The 

 lower level gravels conforming to -the course of the river, are at 

 Kennington and Willesborough, two hundred feet ; Godmersham, 

 one hundred feet; Chilham, one hundred and seventy five feet; 

 Chartliam, about seventy feet ; and Wincheap, fifty feet above the 

 sea level. These gravels are tlie same mixture of Eocene pebbles 

 and subangular flints from the chalk as those of the higher eleva- 

 tions, being in fact the same washed down to lower levels by the 

 river undermining its banks. Owing to some change in the relative 

 heights of sea and land, tidal water at one time flowed higher up 

 these valleys, perhaps to the height of sixty feet at Canterbury, 

 allowing the brick earths to be deposited. The action of tidal rivers 

 dealing with brick earths and gravels may be witnessed at the pre- 

 sent lime in the river Avon at Clifton, where at high water the 

 stream becomes very sluggish, permitting fine alluvial matter 

 to be deposited, whilst at low water the rapid stream tears 

 along stones many pounds in weight. I have seen the tops 

 of isolated piles covered with mud six or eight inches thick. 

 The accumulated mud was last year threatening the framing 

 of one of the lauding stages witli destruction. The brickearths 

 of the Thames valley contain many fresh water and land shells. 

 (Proceedings of Geological Society, 1869, page 99.) Among the 

 gravels are casts in flint, generally much water woi'n, of chalk 



